Variable ND Filters

[Rusty Sprinkles]

Hi guys.

I have only recently realised that there are Variable ND filters on the market. Having just bought a new lens (SIGMA 17-70) I now have to get filters for the 72mm thread. I also have a 58mm Canon Lens. It seems like a good move to go from ND2,4 & 8 filters to one that covers them all.

Does anyone use one of these filters? If so do they work? Would it be worth getting one? I can only afford a lower end price at the moment.

Sat here on night shift and bored!

Thanks.

 

[Mike Jackson]

If you search you'll find that quite a few people have used them and had problems particularly with wide angle lenses.

 

[vizzair]

Somebody correct me if Im wrong, but I think they work by rotating two polarized films to block the light - now I have used this type of polarizer (both linear and circular ) to project 3D images at work, and we have alway found that when you cross them to block the light it always lets the higher frequencies through ( at a much reduced level ), so the image starts to get a purple cast:razz:.

I personally also have a limited budget, so i bought the sevendayshop ND's
so called ND2, ND4 and ND8 and they are very good with very little colour cast, even when stacked. And quite honestly i very rarely use them, usually I use the ND8 maybe stacked with the ND4 to take "nearly" sunsets over the sea to create silhouette effects.

I will also just use the ND8 for waterfalls ( if I ever find one with water in it ! )

 

[Craikeybaby]

You could also consider getting a bigger filter and step down rings.

 

[HoppyUK]

Avoid variable ND filters. Frankly unusable with wide angles, plenty of examples if you search. Much better off with a fixed density.

Also be aware of how density is expressed. NDx2/4/8 are one, two and three stops respectively, also known by optical density 0.3, 0.6, and 0.9 etc. A ten stop extreme ND is around x1,000, technically x1024 or 3.0.